The present invention relates to a method and apparatus for measuring the degree of fullness of an electrically driven mill, which method and apparatus make use of power variations affecting the electric motor of the mill.
In accordance with the disclosure in Canadian Patent 1,135,346, the power consumed by a mill driven by an electric motor, particularly an autogenous mill, varies periodically, and the amplitude of the periodic variation depends on the degree of fullness of the mill. Accordingly, the Canadian patent discloses a method and apparatus for measuring the degree of fullness of such a mill by continuously generating an electric signal representing the variation in electric power consumed by the mill within a relatively low frequency range 2-25 Hz. The degree of fullness of the mill is determined on the basis of the power signal, by utilizing test measurements performed earlier with different degrees of fullness.